A subject in grammar is the noun or pronoun that performs action of the verb. In the following examples, each of the highlighted words (or word groups) is a subject.

  • Who has taken my book?
  • My wife and I have a small house in central Texas?

An infinitive can behave as a subject:

  • Which car to buy is the hard part.

A gerund can behave as a subject:

  • Having such a large house has disadvantages.
  • Ignoring the symptoms could lead to the spreading of the ulcer.